lean into examples

examples/spawning-processes/spawning-processes.go

@@ -0,0 +1,36 @@
+// Sometimes our Go programs need to spawn other, non-Go
+// processes. For example, the syntax highlighting in this
+// book is implementing by spawning a [`pygmentize`]()
+// process from a Go program. Let's look at a few
+// examples of spawning processes from Go.
+
+package main
+
+import "os/exec"
+import "fmt"
+
+func main() {
+    // todo: explain
+    dateCmd := exec.Command("date")
+    dateOut, dateErr := dateCmd.Output()
+    if dateErr != nil {
+        panic(dateErr)
+    }
+    fmt.Println("> date")
+    fmt.Println(string(dateOut))
+
+    // todo: piping in stdin
+
+    // Note that when spawning commands we need to
+    // provide an explicit command and argument array,
+    // vs. being able to just pass in one command line.
+    // If you want to be able to just spawn a full
+    // command, you can use `bash`'s `-c` option:
+    lsCmd := exec.Command("bash", "-c", "ls -a -l -h")
+    lsOut, lsErr := lsCmd.Output()
+    if lsErr != nil {
+        panic(lsErr)
+    }
+    fmt.Println("> ls -a -l -h")
+    fmt.Println(string(lsOut))
+}

examples/spawning-processes/spawning-processes.sh

@@ -0,0 +1,8 @@
+$ go run spawning-processes.go 
+> date
+Wed Oct  3 16:40:57 EDT 2012
+
+> ls -a -l -h
+drwxr-xr-x  4 mark 136B Oct 3 16:29 .
+drwxr-xr-x 91 mark 3.0K Oct 3 12:50 ..
+-rw-r--r--  1 mark 1.3K Oct 3 16:28 spawning-processes.go